diff --git a/fullscreen-shell/fullscreen-shell.c b/fullscreen-shell/fullscreen-shell.c
index abc4e847..a32e46a4 100644
--- a/fullscreen-shell/fullscreen-shell.c
+++ b/fullscreen-shell/fullscreen-shell.c
@@ -294,7 +294,7 @@ restore_output_mode(struct weston_output *output)
 
 /*
  * Returns the bounding box of a surface and all its sub-surfaces,
- * in the surface coordinates system. */
+ * in surface-local coordinates. */
 static void
 surface_subsurfaces_boundingbox(struct weston_surface *surface, int32_t *x,
 				int32_t *y, int32_t *w, int32_t *h) {